Prognostic Meteorological Discussion
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FXUS02 KWBC 281552
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1152 AM EDT THU MAY 28 2015

VALID 12Z SUN MAY 31 2015 - 12Z THU JUN 04 2015

...GUIDANCE/UNCERTAINTY ASSESSMENT...

WPC MEDIUM-RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS HAVE
BEEN PRIMARILY DERIVED FROM A BLEND OF THE 06 UTC GEFS MEAN AND 00
UTC ECMWF/ECMWF ENSEMBLE MEAN. THE MASS FIELDS OF THESE GUIDANCE
CHOICES CLUSTER REASONABLY WELL. THIS GUIDANCE COMPOSITE TENDS TO
MITIGATE MUCH LESS PREDICTABLE SMALL-MID SCALE FEATURE VARIANCE.
THE RESULTANT PATTERN OFFERS AT LEAST AVERAGE PREDICTABILITY AT
MID-LARGE SCALES AND WITH GENERAL SENSIBLE WEATHER/THREAT FOCUS.

...PATTERN OVERVIEW AND SENSIBLE WEATHER HIGHLIGHTS THREATS...

NRN STREAM FLOW INFLUENCE WILL FORCE HIGH PRESSURE ACROSS THE
GREAT LAKES/MIDWEST AND THE NERN US/MID-ATLANTIC IN THE WAKE OF
WEEKEND TO EARLY NEXT WEEK MID-UPPER LEVEL TROUGH PASSAGE AND
REINFORCEMENT. A LEAD WAVY FRONTAL BOUNDARY WILL SPREAD UNDERNEATH
ACROSS THE ERN US AND LINGER ACROSS THE US SRN TIER. LOWER MS
VALLEY CENTERED MID-UPPER LEVEL CUTOFF LOW ENERGY AND FAVORABLE
MOISTURE POOLING ALONG/AHEAD OF THE SLOW TO DIMINISH FRONT SHOULD
FOCUS A CONTINUED LOCALLY EXCESSIVE RAINFALL THREAT...ALBEIT WITH
LESS PREDICTABLE HEAVY CONVECTION FOCUS AT THESE TIME FRAMES.

MEANWHILE...STILL UNSEASONABLY ACTIVE INFLUX OF ERN PACIFIC
MID-UPPER LEVEL TROUGH ENERGIES WILL SUPPORT SYSTEM AND PCPN INTO
THE WRN/NWRN US AGAIN BY EARLY NEXT WEEK...WITH EMPHASIS/HEIGHT
FALLS WORKING ACROSS THE N-CENTRAL ROCKIES AND PLAINS PAST NEXT
MIDWEEK...ALL UNDERNEATH EARLIER PERIOD NRN STREAM TROUGH
PASSAGE/INFLUENCE. EXPECT A SWATH A MODERATE AND TERRAIN ENHANCED
PCPN ACROSS THE REGION...WITH LATE PERIOD PLAINS CYCLOGENESIS
POTENTIAL MIDWEEK PROVIDING POTENTIAL FOR AN ENHANCED LOCAL
CONVECTIVE PCPN FOCUS.

SCHICHTEL



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